This invention relates to a stream data processing system, and more particularly, to an anomaly detection technology and a performance guaranteeing technology that are used for stream data processing.
On a computer for executing stream data processing, pieces of continuously-received data are processed without interruption, and predetermined processing such as determination, complementation, prediction, or anomaly detection is performed. However, an abrupt increase in received data increases latency, and a real-time property desired by a user cannot be maintained.
Therefore, there is known a technology in which a plurality of modes of processing different in processing time and accuracy are provided in advance, and the mode of processing to be used is selected so as to satisfy the latency requested by the user depending on a data amount, to thereby reduce a whole arithmetic operation amount and maintain the real-time property (see Japanese Patent Application Laid-open No. 2010-206486).
Further, in the field of anomaly detection processing, there is known a technology for reducing the arithmetic operation amount by determining, each time data having a given fixed data amount arrives, whether or not an index used for anomaly detection needs to be recalculated based on an accumulating total of a distance between newly-arrived data and the index used so far (see Japanese Patent Application Laid-open No. 2009-199289).